Tag Archives: ST2000XM

M96 in Leo: An Imperfect Spiral Galaxy

M96 - Spiral in Leo

Messier 96 is an imperfect, intermediate spiral galaxy in the constellation of Leo, at a distance of approximately 30 million light years. It is a highly asymmetric galaxy – the gas and dust is not evenly spread through its spiral arms, and the core doesn’t appear to be exactly at the galaxy’s centre. This is thought to have arisen due to interactions with other nearby galaxies (eg M95 which is about 40′ to the west of M96 from our viewpoint).

The spiral arms show bright knots of young hot stars (more easily visible in colour images) indicating recent starbirth, and visible through the outer dusty reaches are many background galaxies including the edge on galaxy 2MFGC 8391 shown here to the lower right (north-east) of the centre of M96. 

Also in this image is my current distance record (though not something I’ve tried to push!) – QSO J104619.26+115223.4 is present (and annotated in the image shown) – this quasar has a measured redshift of z=2.83, placing it at a distance of of 11.4 billion light years (light travel time) in our current best estimates of the universe’s parameters. This quasar shines dimly at a magnitude of 20.5 in the R band. Somewhat closer to home, but equally faint, is the dwarf galaxy Leo 15 (also annotated).

The image was taken on 22 Feb 2018 and 13-14 March 2018 and consists of 7hrs of exposure through the luminance filter (84 x 5min subexposures) using an ST2000XM on a 350mm Newtonian at 1584mm focal length. Processing and reduction took place in Pixinsight.

Weather was very poor this spring and I had no chance to get any decent colour data to produce a finished LRGB version – will have to hold this one over until next year…

Field (25’x18.6′) centred at:
RA: 10h 46m 44s
Dec: +11° 49′ 23″
Up is 184° E of N

M106 in Canes Venatici

Field Centred at:
RA: 12h 18m 41.0s
Dec: +47° 17′ 57.3″
Field 25.2×18.9 arcmin, Up is 184° E of N

M106 (with NGC4248) - LRGBM106 (NGC 4258) is an intermediate type spiral galaxy located at a distance of 23.7 (± 1.5) million light years in the constellation of Canes Venatici. Also shown in this frame is the small spiral galaxy NGC 4248 (lower left of frame).

M106 was discovered by Pierre Méchain in 1781 and has an active nucleus and is one of the best known Type 2 Seyfert galaxies. It also is host to a water vapour megamaser that is visible in the 22GHz frequency of ortho-H20 (water molecules where the spins of the two hydrogen atoms are aligned). 

M106 also has significant hydrogen emission around the core – one of the brighter “jets” is just visible in the close up (at 150%)  – taking hydrogen alpha data would show this up to a much greater extent, but this is something that will have to follow later when skies are clear!

In June 1995, the following letter was published in Astronomy & Astrophysics from Burbidge concerning two bright Xray sources symmetrically placed about NGC 4258 (M106):  1995A&A…298L…1B

Burbidge found that these objects were in fact quasars, with redshifts of 0.39 (J1218+472) and 0.65 (J1219+473). Burbidge, who worked closely with Fred Hoyle, argues (as does Halton Arp in a later paper), that the association of these QSOs with M106 is not accidental, and that the redshifts arise from the ejection velocities of the objects from the host (pretty quick!).

All three scientists were strong proponents of non-Big Bang cosmologies though, so you may detect a slight bias here: later work (eg , http://iopscience.iop.org/article/10.1086/309327/pdf) appears to suggest one of these (J1281+472) is associated with a cluster at redshift z~0.3, and that X-Ray luminosity and cluster temperatures are entirely consistent. So, this may well be a case of line of sight.

In the field as well (see the image, left), is a further QSO with redshift ~1.04 – theory places this at around 8Gly in a flat cosmology.

 

Image was taken with an ST2000XM through a 14″ Newtonian at f4.53 (fl = 1584mm) from West Oxfordshire on Feb 13th/15th 2018. Exposures lengths are:

Lum: 5h35m (56x5m + 21x3m) 
R: 1h45m (21 x 5m, 2×2 bin)
G: 1h20m (16 x 5m, 2×2 bin)
B: 1h20m (16 x 5m, 2×2 bin)

The luminance data on its own is shown below.M106 (with NGC4248) - Luminance Channel

 

 

 

 

 

EDIT: This image was selected in 2nd place for the “A Galaxy, Far, Far Away” challenge on Stargazers Lounge – see: https://stargazerslounge.com/topic/314249-imaging-challenge-11-galaxies-winners/

Merope & Tempel’s Nebula (NGC1435)

Image centred at:
RA: 03° 46′ 18″
Dec: +23° 56′ 04″
Field of view: 25.46′ x 18.82′

Merope & NGC1435 (Tempel's Nebula)The Pleiades open cluster in Taurus is one of the brightest and most recognisable objects int he winter sky. As a first LRGB image using the 14″ Newtonian, and to test the setup of the off-axis guider, I imaged the area around Merope (23 Tau). This was also the first use of a Bahtinov mask that I got laser cut by Oxford Hackspace. The focusing mask works excellently – this should be a real plus, especially for any planetary/lunar work.

The particular area of nebulosity imaged here around Merope was discovered by Wilhelm Tempel on October 19th, 1859, and is catalogued as NGC1435. The dust isn’t in fact the nebula from which the cluster formed, rather that the Pleiades happen to be travelling through a particularly dense part of interstellar medium. This dust scatters blue light from the cluster members, resulting in the reflection nebula visible to us.

The image shows strong diffraction spikes from the secondary spider, as would be expected. There’s also further diffraction visible around the brightest stars dark shadowing present at 60 degree angles, which is the result of the mirror retaining “clips” (they are not actually clips – they are part of the cell in the case of the 9 point Orion Optics mirror cell). To remedy this would require a mask to be added over the outer edge of the mirror to cover these over – this is maybe something I’ll think about making in the future to help deal with tricky situations like this! 

The additional dark shadow pointing to the right appears to be the focuser drawtube intruding on the internal light path inside the scope – that’s probably something that can only be cured by either a shorter drawtube, or shortening the truss tubes. Again. Maybe I’ll wait in case I decide to change coma corrector at some point, in which case it’ll probably need a change to the focal plane position anyway.

The image was taken on the evening of the 7th Jan 2018 through the 14″ (350mm) Newtonian, with an ST2000XM and an MPCC v1 coma corrector. Total exposure was “only” 2h 32m (L: 59m (20x1m, 13x3m), RGB: 31m (10x1m, 7x3m) each channel). Processing in Pixinsight and Photoshop CS4.

IC1396A – Elephant’s Trunk Nebula

Image centred at (nova.astrometry.net plate-solve):
RA: 21h 34m 17.296s
Dec: +57° 30′ 37.211″
Up is 2.19° E of N

IC1396 is a very large region of HII emission located in the Milky Way within Cepheus, which spans over 5 degrees of sky. Within IC1396, to the western side, is the Elephant’s Trunk Nebula, known as IC1396A, and VdB 142, which is a reflection nebula at the end of the “trunk”.

IC1396A - The Elephant's Trunk Nebula in Cepheus - LRGBIC1396A itself is a dense globule of gas and dust that appears to be lined by bright pink emission from atomic hydrogen. This emission is due to excitation by the giant triple star system HD 206267 (off field to the left). The globule appears to be an area of star formation, and contains two young stars in the head of the globule that have created a cavity by the action of their own stellar winds. 

These F-type stars provide the illumination for the rare yellow reflection nebula seen in the head of the globule, as well as the radiation causing the pink hydrogen emission within the cavity. The combined action of HD 206267 and the two young stars has resulted in areas of high compression in the nebula, triggering the formation of protostars.

Data was captured on the night of the 21st September 2017 from West Oxfordshire. Image details are as follows:

L:R:G:B = 130:45:35:35
(L:10m subs, RGB: 5m subs, 2x bin)

Taken using a WO FLT110 @ f5.6 with SBIG ST2000XM, on Losmandy Titan.

Processing was performed in Pixinsight – control over the star sizes is tricky here, and I may try and improve on this later. There’s also a (relatively) small amount of data used here – this is certainly a subject that would benefit from adding more exposure (which may also help with star control), as well as H-Alpha data to increase signal and contrast in the emission nebula areas.

Simeis 57 – Propeller Nebula in Cygnus

The Propeller Nebula (Simeis 57) in Cygnus - 7hrs ExposureI had opportunity on the 19th/20th September 2017 to add another 3h40m of exposure to my previous image of the Propeller Nebula (Simeis 57/ DWB111/119) – see “A Crescent and A Propeller” for the previous version. Here is the reprocessed version of the data, taken through an H Alpha filter, which is centered at RA: 20h 16m 08s, DEC: +43° 40′ 42″ (plate-solve from nova.astrometry.net).

Simeis 57 - Annotated with Simbad query resultsThe extra time on this subject has brought out some of the fainter background nebulosity and enhanced dark nebulae in the field. The image at left is an annotated image (using the Image Solver and Annotate Image scripts in Pixinsight). As shown, the Propeller itself is catalogued as DWB111 (south) and DWB 119 (north), with DWB118 representing the surrounding nebulosity, with DWB 108 further to the south below the southern “prop”. There are a few catalogued dark nebulae in the field – Dobashi 2501; Dobashi 2511/TGU H469 P16 which sits between DWB118 and DWB 107 (off field to lower left); and TGU H469 P18 to the west of the main nebula. 

For more information about this region, and pretty much the only bit of published research I can find on it(!), see the paper “Israel, F.P. , Kloppenburg, M., Dewdney, P.E., Bally, J. (2003), The peculiar nebula Simeis 57, Astronomy and Astrophysics, 398, 1063 – 1071“.

All data was taken from West Oxfordshire on 9th/10th and 19th/20th September. William Optics FLT110 @f5.6 on a Losmandy Titan, SBIG ST2000XM CCD and an Astrodon 5nm HA filter.